Determining a model to estimate leaf area in Pornunça (Manihot sp.) using morphometric measures

ABSTRACT. Pornunça is a species of the genus Manihot that has been cultivated as an option for animal feeding in the Brazilian semi-arid. Leaf area (LA) is important to determine forage plant growth, whose evaluation model has to meet the following characteristics: practicality, precision and low cost. The objective of this study was to set a model to determine the leaf area in Pornunça (Manihot sp.) from morphometric measurements of the leaf. The experimental design was in randomized blocks with three methods for determination of leaf area, and three blocks, with 144 replicates (leaves). For the determination of LA, the direct method (FAReal), treadmill leaf area meter (Li-Color 3100©) and linear dimensions were used. Data were subjected to regression analysis. There was a relationship between the actual leaf area (FAReal) for small, medium, large and total leaves, and the leaf area determined by the treadmill leaf area meter (FALi-Cor©) with a high coefficient of determination for linear fit. The Pornunça leaf area obtained by the Li-Cor3100© meter is approximately 10% lower compared to the FAReal method. The model that best fit the Ponunça leaf area estimation was the potential.摘要。波鲁努萨（Pornunça）是木薯属（Manihot）的一个物种，在巴西半干旱地区被作为动物饲料的备选栽培作物。叶面积（Leaf Area, LA）是评定饲用植物生长状况的核心指标，其评估模型需兼具实用性、精准性与低成本三大特性。本研究旨在通过叶片形态测量参数，构建用于估算波鲁努萨（Manihot sp.）叶面积的预测模型。 试验采用随机区组设计，设置3种叶面积测定方法，共3个区组，包含144个重复样本（单叶）。叶面积测定分别采用直接法（FAReal）、台式叶面积仪（Li-Color 3100©）法以及线性尺寸测量法。对所得数据开展回归分析。 研究发现，针对小型、中型、大型及全部叶片的实际叶面积（FAReal），与通过台式叶面积仪（FALi-Cor©）测得的叶面积之间存在显著线性相关关系，线性拟合的决定系数较高。相较于FAReal直接法，Li-Cor3100©仪测得的波鲁努萨叶面积约低10%。最适配波鲁努萨叶面积估算的模型为幂函数模型。